Investigating SnowFlat theme further, I just think, why do we use an icon font (which is quite good !) and then additionally many png images that represent icons (which is not so good, each icon is one request to the server). See folder images/icons.

PS: If the png images cannot be replaced by the icon font, I advice to use one big image that holds all icons and then reference by background-position. All big sites are doing that nowadays... or use font icons :)